Erratic Windows Loading Times

[IwantanewPC]

When I boot my PC and it gets to the Windows XP loading screen (the black one) sometimes it'll be on for about 7-8 seconds before it moves on to the windows xp logon screen where as other times it'll hang on it for about 20-40 seconds before finally moving on.

I don't understand why this happens? it happens when i've made no changes to my pc (installed something or changed settings)

any ideas?

 

[IwantanewPC]

I just downloaded Bootvis and used it, and when I opened it after rebooting it says,

'Warning! Disk write caching is disabled'

What does this mean? Is it serious?