The Lenovo ThinkPad X61 is still a great small laptop and was used by many companies. It still has life left in it and you can Install Windows 7 on the Lenovo ThinkPad X61 very easily.
For my test I installed Windows 7 Home Premium With Service Pack 1 64 Bit. Since the Lenovo ThinkPad X61 does not have an optical drive I used an external optical drive but you could probably use a flash drive as well.
I did a clean install keeping nothing and after running Windows Update there were no more drivers that I needed to install.
Despite some of these Lenovo ThinkPad X61’s coming with Windows Vista Basic, Aero Glass was enabled and supported in Windows 7.
Windows 7 on the Lenovo ThinkPad X61 performs very well and is up to most tasks. It should be just fine for business use but I would advise against gaming or anything overly graphical. Below is the Windows Experience Index.
If you have one of these around and are thinking of upgrading to a newer version of Windows I feel like you should install Windows 7 on the Lenovo ThinkPad X61 and give it a shot.