Window 7 downgraded to XP blue screens

Hi, i need help and it might be a little hard to explain.

My Windows 7 started to show some problems and had to downgrade to XP. Now i keep getting random blue screens (or sometimes a white out of focus screen). Everytime the code is different.

I believe my notebook (Acer Aspire 4540) drivers are not compatible with XP, but i can't be sure.

My question is if i can reinstall Windows 7 without CD after formatting to XP? I have the serial number in the back of the notebook, and found this tutorial online. Is there any part of my original Windowns 7 in the notebook after the format? Will the tutorial work? So simple, just download the ISO file for my version of Windows 7 (i can't remember the version too)?

I'm not sure because i had problems in the past and i don't know if tech support installed the same version that came with the notebook. Before formatting it was Windows 7 Ultimate but i don't remember if it was 32 or 64 bits.

But the code will only work with the original version right? So if download the wrong version what happens?

Edit: Had to loggin to see the image. Thanks, i'll see how it goes and let you guys know.

AddRAM said:

It doesn`t matter if it was 32 or 64 bit, the same key can activate both.

If you install the wrong version, you won`t be able to activate it.

But you can`t find the key anyway.

I`m sorry but computers don`t come with Windows Ultimate pre installed, Ultimate is something you would buy yourself and install.

99% of PCs sold to the public come with Windows Home Premium 64 bit, but in your case it could have been Basic or Starter.

Acer Aspire 4540-1047 - 14" - Athlon X2 M300 - Windows 7 Home Premium 64-bit - 4 GB RAM - 320 GB HDD Overview - CNET

Acer Aspire 4540-5531 Notebook Laptop specs

There is no reason at all to install XP on a Windows 7 computer, none whatsoever

I agree. But it was the only way i found to to make my notebook to work again. I was desperate and didn't know if it was possible to install (or format actually) Windows 7 without the CD.

The back of my note has the key, but the part that says which version is no longer visible. I will download Home Premium 64 bit tonight and see how it goes tomorrow.

It is almost certainly Home Premium: Win7 Home Premium x64 SP1 English Official ISO download

Then follow the steps carefully in Clean Reinstall - Factory OEM Windows 7 and you will get and keep a perfect install if you do.