I would try searching for files containing the word omnipage or words similar.
You could try omni or se40 or 1316.

If it finds something , open the folder and if it is obvious that folder contains the files to run your unwanted program , dump it to the recycle bin.

It won't be the same as uninstalling , but it should release your 100 Megabytes to you.

Just beware if you dump stuff and then empty your recycle bin, then it is GOOOOONE!!!.