Windows 7 pro 32bit to 64bit

After i recently went through a series of mishaps and bad luck my HP ProBook 4520s had to have its hard drive replaced. During its repair process i had an extra 4gb ram put in so i now have a total of 8gb ram. Sadly only 2.98gb is usable.

now here is my problem: -my computer has Windows 7 pro 32bit pre installed
-my computer did not come with an installation disk for windows
-I would like to upgrade to 64bit with a clean re-install
-How can install windows 7 64bit without spending more money?


ps: I do have the serial for my computer's windows 7 (not sure if it only works on 32bit)
pss: I understand that this might be a common question but please let me know if you have any suggestions.

also yes my computer IS compatible with 64bit

your serial for pro 32 will work with pro 64. go to MS and download the iso file for windows 64 then install it using your current key.

Have a look at these threads in Microsoft Answers. ( These apply to changing over from 32 bit to 64 bit version or viceversa and clean installing from a non-OEM disk )

Convert 64 bit to 32 bit on new Windows 7? - Microsoft Answers

Can I use Windows 7 OEM Key with a non-OEM disc? - Microsoft Answers

You may download Windows 7 Professional 64bit from Official Windows 7 SP1 ISO from Digital River « My Digital Life

From Jumanji's link, you need this, assuming you want the English version. This is Win 7 Pro with SPI.

English x64: X17-59186.iso

Burn the ISO to a disk and boot from that disc.

Make sure you have the 25 character Product Key from your existing installation.

Disconnect all hard drives other than the one that will receive Windows 7--if you have more than 1 hard drive.

Back up your data before you start.

Delete all partitions by choosing "drive options, advanced" when you come to the "where do you want to install Windows" screen.

It isn't necessary to go to MS for this as SevenForums is the top resource on the net for clean reinstalling Factory OEM Win7..

You're entitled to use either 32- or 64-bit Win7 with each license, and you can reinstall Windows as often as you want in either flavor.

Everything you need is here: Clean Reinstall - Factory OEM Windows 7

I believe that the HDD change was done by HP and in that case the OEM activation is preserved by HP. You may not have a recovery partition and in that case HP would have installed the Windows 7 Pro 32 bit version with the OEM installation disk. ( If you do have a Recovery partition, please do make your Recovery Disks)

You can confirm what key is being used by your current installation by running a Product Key Finder. ( You can use Speccy for this.)

If the key found is different from the one in the COA sticker on your machine, then your machine still uses the OEM activation, which is perpetual and auto-activates when installed with OEM Reinstall Disk/Recovery Disks. ( It does not depend upon the vagaries of Microsoft servers or the whims and fancies of the person at the other end if you need to do a phone activation with COA-SLP key.)

If you want to change over to COA-SLP Key (on the sticker ), I would advise that you back-up your current installation which contains all the OEM activation data and keep it safely. ( just in case you run into any problems with COA-SLP activation now or in future. Judging from various reports, I do not discount this possibility.))

In countless thousands of Clean Reinstall - Factory OEM Windows 7 we've helped with here I have never seen one that did not activate with the Product Key on the COA sticker. The ankle-biting on this is growing tiresome.

Thanks for the speedy replies I'll try out those options tonight