Hello S.name, welcome to the Microsoft community, I'll be happy to help you today;
I understand that the PC is slow after spending a few months without using it;
First of all I need you to answer the questions below;
What exactly is the model and manufacturer of your graphics card?
What exactly is your PC model and manufacturer?
If it's a desktop, what exactly is the model and manufacturer of the motherboard?
Before answering the question I suggest you try the following;
Check if you are updated with the latest version of Windows 10;
Press Windows key + i and go to Update and Security;
Click Check for updates and do ALL pending updates;
Update apps from the store;
Open Microsoft Store and click Library;
Click Get Updates and wait until all apps are updated;
run a disk cleanup;
Press WIndows key + R and type: cleanmgr press Enter;
Click Clean System Files and wait for the files to load;
Select all items and click Ok to delete them;
Do a clean boot;
Press the keys: Ctrl+Shift+Esc to access the task manager;
Click Startup and disable all programs that start with Windows;
Restart the PC and check if the behavior persists;
See you soon!