Are the deeds performed by a person using his computer, including financial gain, invalidated if it is found that one of the computer's tools was purchased with illicit money, despite his initial efforts to ensure the lawfulness of the money?

There is no harm in using and working on a computer, even if some of its components were purchased with illicit or questionable money, because that does not prohibit the use of what is done on the device. These thoughts are whisperings from Satan that must be disregarded.