The TiVo is an old box running old hardware, there's no getting around that. If you're using streaming apps or OnDemand a lot, and you have VM broadband, you'd get a much better experience from having a V6. However, all that said...
All the issues you've mentioned are symptomatic of a TiVo with internet issues. This box has its internet connection inbuilt and doesn't use your home broadband. Quite often issues with streaming & VoD are caused by the 'net connection failing.
On the front-left of your TiVo are a series of green lights. Second from left has a painted heart symbol next to it, and represents the online status. If ever this flashes, it means the onboard cablemodem is failing, which will cause precisely the issues you describe.
Is yours flashing? Once you can confirm that (and therefore whether this is your issue) we can advise the best way forward.
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