What do these messages in the logs (every second)? 

 "RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:38:31 vn-HP-ProBook-4740s kernel: [16249.763275] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:38:36 vn-HP-ProBook-4740s kernel: [16254.757350] ===>rt_ioctl_giwscan. 1(1) BSS returned, data->length = 222
Apr 17 14:38:51 vn-HP-ProBook-4740s kernel: [16269.753565] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:38:59 vn-HP-ProBook-4740s kernel: [16277.741674] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
....
Apr 17 14:55:09 vn-HP-ProBook-4740s kernel: [17246.640203] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:55:11 vn-HP-ProBook-4740s kernel: [17248.638925] Rcv Wcid(1) AddBAReq
Apr 17 14:55:11 vn-HP-ProBook-4740s kernel: [17248.638933] Start Seq = 0000002f
Apr 17 14:55:11 vn-HP-ProBook-4740s kernel: [17248.639832] Rcv Wcid(1) AddBAReq
Apr 17 14:55:11 vn-HP-ProBook-4740s kernel: [17248.639838] Start Seq = 0000002f
Apr 17 14:55:15 vn-HP-ProBook-4740s kernel: [17251.978729] Rcv Wcid(1) AddBAReq
Apr 17 14:55:15 vn-HP-ProBook-4740s kernel: [17251.978736] Start Seq = 00000034
Apr 17 14:55:27 vn-HP-ProBook-4740s kernel: [17264.009344] 62, flush one!
Apr 17 14:55:32 vn-HP-ProBook-4740s kernel: [17268.901035] Rcv Wcid(1) AddBAReq
Apr 17 14:55:32 vn-HP-ProBook-4740s kernel: [17268.901043] Start Seq = 0000006e
Apr 17 14:55:32 vn-HP-ProBook-4740s kernel: [17269.343655] 81, flush one!
Apr 17 14:55:33 vn-HP-ProBook-4740s kernel: [17269.841179] 9c, flush one!
Apr 17 14:55:40 vn-HP-ProBook-4740s kernel: [17277.024557] 148, flush one!
Apr 17 14:55:48 vn-HP-ProBook-4740s kernel: [17284.805045] Rcv Wcid(1) AddBAReq
Apr 17 14:55:48 vn-HP-ProBook-4740s kernel: [17284.805051] Start Seq = 00000172
Apr 17 14:55:48 vn-HP-ProBook-4740s kernel: [17284.806848] Rcv Wcid(1) AddBAReq
Apr 17 14:55:48 vn-HP-ProBook-4740s kernel: [17284.806850] Start Seq = 00000172
Apr 17 14:55:48 vn-HP-ProBook-4740s kernel: [17285.280756] 179, flush one!
Apr 17 14:55:57 vn-HP-ProBook-4740s kernel: [17294.568938] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:55:58 vn-HP-ProBook-4740s kernel: [17294.695869] Rcv Wcid(1) AddBAReq
Apr 17 14:55:58 vn-HP-ProBook-4740s kernel: [17294.695877] Start Seq = 000001ac
Apr 17 14:55:58 vn-HP-ProBook-4740s kernel: [17294.696741] Rcv Wcid(1) AddBAReq
Apr 17 14:55:58 vn-HP-ProBook-4740s kernel: [17294.696745] Start Seq = 000001ac
Apr 17 14:56:21 vn-HP-ProBook-4740s kernel: [17318.533289] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:56:35 vn-HP-ProBook-4740s kernel: [17332.513850] ===>rt_ioctl_giwscan. 1(1) BSS returned, data->length = 222
Apr 17 14:56:49 vn-HP-ProBook-4740s kernel: [17346.511630] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:57:21 vn-HP-ProBook-4740s kernel: [17378.468089] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:57:40 vn-HP-ProBook-4740s kernel: [17396.914431] 22e, flush one!
Apr 17 14:58:01 vn-HP-ProBook-4740s kernel: [17418.408702] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:58:29 vn-HP-ProBook-4740s kernel: [17446.367143] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:58:35 vn-HP-ProBook-4740s kernel: [17452.359444] ===>rt_ioctl_giwscan. 1(1) BSS returned, data->length = 222
Apr 17 14:59:08 vn-HP-ProBook-4740s kernel: [17484.434452] RTMP_TimerListAdd: add timer obj ffffc9002277dab8!
Apr 17 14:59:18 vn-HP-ProBook-4740s kernel: [17494.315850] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI
Apr 17 14:59:22 vn-HP-ProBook-4740s kernel: [17498.309830] RT3290_AsicTxAlcGetAutoAgcOffset: Incorrect desired TSSI or current TSSI



"
while now sucessfuly doing wifi, but not stable (after reinstall driver rt3290  by instruction in  http://askubuntu.com/questions/253632/how-do-i-get-a-ralink-rt3290-wireless-card-working
and for kernel 3.7.2-030702-generic )

?

- Device: ra0  [CPB_IT 1] ------------------------------------------------------
  Type:              802.11 WiFi
  Driver:            rt2860
  State:             connected
  Default:           yes
  HW Address:        A4:17:31:3C:0F:93

  Capabilities:
    Speed:           65 Mb/s

  Wireless Properties
    WEP Encryption:  yes
    WPA Encryption:  yes
    WPA2 Encryption: yes

  Wireless Access Points (* = current AP)
    *CPBn:         Infra, 10:BF:48:92:65:08, Freq 2437 MHz, Rate 16 Mb/s, Strength 100 WPA2

  IPv4 Settings:
    Address:         192.168.1.10
    Prefix:          20 (255.255.240.0)
    Gateway:         192.168.1.33

    DNS:             192.168.1.33

....
lspci -vnn
..
04:00.0 Network controller [0280]: Ralink corp. Device [1814:3290]
	Subsystem: Hewlett-Packard Company Device [103c:18ec]
	Flags: bus master, fast devsel, latency 0, IRQ 19
	Memory at d0610000 (32-bit, non-prefetchable) [size=64K]
	Capabilities: <access denied>
	Kernel driver in use: rt2860
	Kernel modules: rt3290sta, rt2800pci
.......



It is normal that not
  RT3290 appears as a driver, and
Driver: rt2 ?