Most of the time you really don't need to install the software that comes with mice/keyboards unless the mouse/keyboard has some fancy buttons you'll probably never use anyway. Most of the time if you just plug it/them into your computer and turn it on, the operating system will install generic drivers which will enable functionality of the devices. Oftentimes the software they want you to install is bloated crapware that runs in the background always
, and is oftentimes unnecessary.
Having said that, I don't think the software (even if it was installed) would/should impact the performance of the computer to that great a degree unless the computer was underpowered to begin with (or had an insufficient amount of memory installed).
More likely it's malware, like others have suggested. Try doing a full scan with the installed antivirus and try scanning with Malwarebyte's Anti-Malware...
Be sure to uncheck the free trial of Malwarebyte's Anti-Malware Pro (or whatever they call it) during install. Also, go into Settings and have it scan for rootkits too.