Use WMIC to list all the installed Windows updates, and output it to a file:

wmic qfe list brief /format:texttablewsys > UninstallKB.txt

Then, use Excel, or Word to extract the column with the HotfixID into a file.

Finally, use the following command to uninstall all the updates:

for /f %1 in (UninstallKB.txt) do start /wait wusa.exe /kb:%1 /uninstall /quiet /norestart