Cannot Acess WEB using MSN or AOL

I am presently using Windows 95 and MSN internet access on a computer at my office. Ihave been unable to access the Web on both AOL and MSN. I can receive mail on AOL but cannot on MSN. Several people have told me that I have to reinstall windowsfrom scratch. This is not a realistic task as I presently have a payroll program (ADP)that uses various areas of windows and if I uninsall windows ADP will charge a large fee to reinstall their portion of the program. I can connect to each ISP withno problem its just getting out to the web and sites.