problem with download Accelerator

[vev_pro]

I Hav Win Xp Sp2.
Last Week I Ran Norton Disk Doctor Unfortunately Drive Letters Got Interchanged After That Whenever I Click A Link On internet Explorer(ver 6) it Gets Closed.also download Accelerator (ver8) also Closes When I Try To Download Something.plzz Help Me

[pip22]

Try running System Restore -- choose a restore point dated before the date you ran Norton DD if available.
Start->All Programs->Accessories->System Tools->System Restore