If your copy of the OS is an OEM version, the OS must go with the machine you are selling, You can clean it off but OEM copies are locked into the machine that they came on.
If it is a full retail copy of the OS. Then you can uninstalle it by a clean format of the machine you are selling. There are program available that you can boot from the CD rom and then write Zeros to the whole hard disk.
Which version of the OS do you have?
Rich
My Computer
Computer type
Laptop
Computer Manufacturer/Model Number
Toshiba Laptop Qosimo X870
OS
Windows 7 Pro x64 SP1
CPU
Intel Core I7
Motherboard
Toshiba Qosmio
Memory
16 Gigs
Graphics Card(s)
NVIDIA GeForce GTX 670M
Monitor(s) Displays
17.7" laptop
Screen Resolution
1600 x 900
Hard Drives
256 Gig SanDisk SSD for C
256 Gig Intel SSD for D
Internet Speed
50/25 FIOS
Antivirus
Vipre (all you can eat for 10 machines)
Browser
IE and FF
Other Info
I have dos 6.22, wfwg 3.11, win98, 2000 and xp VHD's available for testing. MS's Virtual PC works great.
1*Samsung 840 EVO 120GB SSD;
1*OCZ Vertex 2 60GB SSD;
2*Samsung F3 SpinPoint 1TB in RAID0;
1*Samsung F1 SpinPoint 1TB;
2*Western Digital 1TB External USB 3.0
1*Western Digital 500GB External USB 3.0
1*Seagate 500GB External USB 2.0
PSU
Thermaltake ToughPower QFan 750W
Case
Thermaltake Element S VK60001W2Z
Cooling
Corsair H60 Water Cooling, 2*230mm and 2*80mm case fans