I've never had a problem with WPA/WPA2 on several different Win7 machines at home and family & friends, and 100+ at work.
I'm unsure exactly what's causing the problem with your PC, if I'd been through all of that I would probably try a clean install (or, preferably, use an Ethernet cable, but I know that's not always possible).
So, yes, WEP will keep your network safe from the casual bystander, but not anyone who puts a few minutes into breaking in to use your connection. I would not want to run WEP myself unless I had no nearby neighbours who might want to borrow my network, but I'm fairly security conscious in that respect.