Likely suspects:

• Disk at 100% active time (old HDD); check with Task Manager and SMART.
• Insufficient RAM forcing constant paging.
• Thermal throttling when dust builds up.
• Background updaters, browser extensions, or malware.
• Driver conflicts (storage, GPU) after a recent update.

Need help? Check here: /services/computer-maintenance/

What it might be (likely causes)

• Disk saturation (especially HDDs)
  If the drive spends long stretches at 100% active time, everything else starves. Aging HDDs with SMART errors (reallocated/pending sectors) are common culprits. Context and upgrade notes: /posts/speed-up-old-laptop/ and /posts/top-problems-10-year-old-pcs/