WiFi stopped working ,help!

Thanks for reply but I already tried that and windows startup error is " device driver software was not successfully installed "....problem is that when I try to install the driver it says the device is not present

Are you installing the correct driver? in device manager does it show at all? If it does then try ti identify the hardware and search for the correct drivers on the Internet. If they install then Windows 8 left behind a Windows 8 driver that may be incompatible with Windows 7.

If this doesnt work, are you happy with PC sugery? The wifi card could be faulty (the upgrade/downgrade of Windows would not cause this), but in the first instance I would turn off the laptop, remove tha battery and the power cord, and remove the wifi card. it is usually be behind a pannel on the bottom of the lapop, but not always. There are 2 wires at the top of the card, normally one black and one white. Gently prise these off.The cards are normally held in with one small screw and are spring loaded so be careful not to loose the screw when the card pops up. gently pull the card out of its socket. Be careful not to touch the terminals, and then put it all back together again in the reverse order. Dont overtighten the screw. The 2 wires that plug onto the top of the card can be a bugger to get back on - dont force them - several attemps will get it on eventually. Finally replace the cover and replace the battery. Hopefully reseating the card will be enough to allow it to be detected and the drivers to be installed.

If this doesnt work then perhaps consider replacing the card, but I have never seen a broken one, so it probably does work.

OK..I'll try each step but im a bit sceptical about disassembling the maxhine ,I'll leave that option for last. I'm also pretty sure I'm installing the correct driver but I could be confidently wrong.what is the most efficient method to finding the correct driver would u say? Before I decide to open the PC

Go to device manger and double click the wifi card. it will bring up a box.
Click on the device tab
There it tells you the device name if you are lucky, but the device id is just as good. Something like PCI/VEN_123ABC&DEV_456DEF
Look this code up in google and see what drivers are available.
Virus check the downloaded file before you do any installing!

OK got it ,will do so now