Computer Running Slow

My computer has recently started to run a lot slower than normal,
It has a AMD Athlo(tm) 63 X2 Dual Core Processor 2400+
2GB Memory
250GB Hard Drive
Anybody no why it is running slow or anything i could do to check things?
Answer #1
Your harddisk could be almost full
you need to defrag your harddisk
maybe spyware is making your pc slow
heavy programs are runnig in the background (like virusscanners)
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