Hey man,
I would say you're right with the wireless card maybe having issues.
1. Simply go into device manager, uninstall wireless driver. Download the new drivers/up-to-date and install them. Reboot and see if that works.
If not
2. Pull your PC apart, get some compressed air, i get mine for $17.50 for 400g. Take your wireless card out and inspect for anything melted incase it over heated and broke, check for any damage at all really. Spray the pci slot. Put the card back in tightly and make sure it doesn't wiggle. Reboot PC and see how you go.
if not
3. Factory reset your wireless router in case some of the settings in there have accidentally been changed for the worse.
if not
4. If you have a second tower PC with a working wireless pci card you could actually take it out, put in the potentially broken one, boot up and see if it works. If it works then the wireless card is fine, its your pci slot or motherboard that maybe the one with the fault.
Let me know how you go because I have other steps.
- LE