Laptop taking absolutely forever to boot up

Alright, I got rid of Vista on my mother's laptop and installed Windows 7 Home Edition on it. Now, for some reason, it takes like 20 minutes to boot up. Apparently, it has something to do with Vista originally being on there and the motherboard BIOS or something doesn't really work too well with it or whatever, that's what my uncle is saying. Now, my mom has been pestering me to put Vista back on it...

I absolutely refuse to put shitty shit resource hogging and crashing Vista back on there, since that was what my mother complaining about in the first place with Vista, and now she wants it back to continue pestering me more about the crashing and slowness. I use the laptop too at times

If this fix involved updating the BIOS, how do I figure out what motherboard the laptop is using to find the latest BIOS update that will work with this thing? If I cannot, will installing Ubuntu 12.04 (this is an older laptop, and 12.04 works better with older laptops) fix this problem?

Any help is welcomed

Ok I need more info ,

1) did you did a clean install of windows 7 ( wipe de drive and install windows )

2) when it takes forever to load , does it pass the bios POST, where does it take forever to load ?

3) what laptop do you have ?

4) Really 20 minutes ?

5) Was the laptop with vista also delayed to boot that much ? 

6) what specs the laptop have? 

Waiting for same answers :)