BOIS 2.0.6a2010 update and fan failure

I am perplexed...I have read and I have updated to the 2.0.6a2010 update as suggested by Dell, after my system fan started running loudly.

That did not help in fact it only slowed down my log on process, (which is still running slowly).

I replaced the fan and after a day the problem came back and continued. I am running a XPS ONE and although it is an older machine it was running just fine, until I started getting the fan failure message. I

am not terrifically computer iterate I just want to know is there a fix or is it a hardware problem????

What must I do in order to get my system back in working order????

I am on a budget and a new system is not in my future for another year!!! I could afford to get some new hardware if it's not too pricey does anyone have a clue of what is need??? thanks!