Microsoft office error

hye,i just installed IS2011 for 2 years.....

but after that,i can't run microsoft office...

windows prompt "there is not enough memory or hard disc space to run word"

but when i check my pc memory,hard disk C still have 76GB and hard disk D still have 250GB...

and my RAM still have 2GB after deducted from 3GB total RAM.....

what's really happen????

if not,can you guys teach me how to reformat hard disk C and how to start configure windows after reformat step by step??