Ugh - I've got Windows Police pro

In fact I've got it really bad!  My computer now will only start in the safe mode.  If I try to start it in normal mode, all I get is several warnings, and then a black screen.  It's running XP (R) (Build 2600.xpsp_sp3_gdr.090206-1234: Service Pack 3).  I tried running my Norton 2009 Antivirus several times, but that seemed to only make things worse.  When it would still load normal windows, it wouldn't run any of the exe files, not would it connect to the internet.  I also turned it off and restarted it a number of times.

 

Though I can build a computer from scratch, and run most software without difficulty, but I have to admit that I'm pretty hopeless when it comes to working within the operating system.  I can do it, but will need step by step guidance - Sorry!

 

Any help you can give me to untangle the mess will be gratefully appreciated.

 

Many thanks,    Susan