This will help you customize the Manufacturer's details for your system, if you are unsure about going through regedit to do this then use the free download at the bottom of the page, it a small program called WinBubble.
Always back up your registry!
1. In regedit go to;
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\OEMInformation 2.
To Add a Logo Image Of Your Choice; The logo must be a
BMP image file and cannot be bigger than 120x120 pixels in size.
In the right pane, right click on a empty area and click on New and String Value.
Type Logo and press Enter.
Right click on Logo and click on Modify.
Type in the full path of the logo BMP file location and click on OK.
EXAMPLE: C:\Windows\System32\Bugsy.bmp
3.
To Add a Manufacturer Name; In the right pane, right click on a empty area and click on New and String Value.
Type Manufacturer and press Enter.
Right click on Manufacturer and click on Modify.
Type in a manufacturer name (ex: Joe Bloggs) and click on OK.
4.
To Add a Model Number; In the right pane, right click on a empty area and click on New and String Value.
Type in Model and press Enter.
Right click on Model and click on Modify.
Type in a your computer's model number and click on OK.
5.
To Add Support Hours; In the right pane, right click on a empty area and click on New and String Value.
Type in SupportHours and press Enter.
Type in your support hours and click on OK.
6.
To Add a Support Phone Number; In the right pane, right click on a empty area and click on New and String Value.
Type SupportPhone and press Enter.
Right click on SupportPhone and click on Modify.
Type in a phone number and click on OK.
7.
To Add a Support Website URL Address; In the right pane, right click on a empty area and click on New and String Value.
Type SupportURL and press Enter.
Right click on SupportURL and click on Modify.
Type in your support URL web address and click on OK.
8.
Close Regedit.ALTERNATIVELY;You can download
WinBubble from the link Below if you prefer the easy option, i have not tried WinBubble myself as did my OEM Info from the method above.
http://www.softpedia.com/progDownload/W ... 88888.html 
So this is where you need to be to be able to change the OEM Info using the 1st method
