Driver problem

Hello,

i have a compaq preasrio f500 and recently i have lost the connecton to the wireless router that i have from bt..the wireless card in my laptop is fine as i tried this in anothe pc, is there any sites that i can get a free download of a driver, or do i need a new motherboard to sort this out,, i was told that if you do a system restart it might sort the problem but no garentee,,any help would be great,,as a cheap fix i had to buy a wifi adaptor but just want my laptop to work like when i bought it a 2 years ago