In addition to PSCOWBOY's post, It woudlnt hurt to run some Virus scans, Also run C-CLEANER to clear computer cookies, index.dat files, temp files, clipboard, memory dumps etc etc,
IF you're experiancing a slight delay at start up, even after you have tried a clean reboot ( see post above )
Then this could indicate a driver
\service taking a little while to "start"
Perhaps run windows update.
Also check for driver updates\newer versions.
If you have lots of programs\toolbars installed that you no longer require,