Is it worth repairing
I have a Toshiba 875-S7310 that has a bad sound card and touch-pad. Is it worth repairing and how.
The audio chipset on this laptop is on the motherboard, so if it's confirmed to be a hardware issue it's usually not worth the cost sadly. It's not unusual for motherboards to be ~60-80% of the cost of a new laptop (or the same price as a like for like used replacement which isn't as easy with Toshiba to do). This issue also hits USFF desktops hard as well. Try reinstalling the driver and hope for the best, otherwise if that doesn't help reinstall Windows and pray it works. You can find the driver here: Support Home (dynabook.com). If all of this fails, it's the motherboard especially if you defaulted the BIOS settings out.
As far as the trackpad goes, check the connections inside. However, it may be as simple as it was disabled in error, since a lot of laptops make that way easier than it should be. Tap on all four corners one at a time 2-3 times and see if that helps first.