IE6 reinstalling after ie7

I got this BIG problem – installed ie7 – not working so I unstall it with windows remove program. now my ie6 is also gone!!!!

Tried to use the ie6 installer but keep getting error message ” a previous installing has pending work requiring a reboot….you need to restart your computer….” I am on XP

I have reboot my computer for 2 weeks now, still can work. anyone out there please help…..