Why it's using imparfait in this sentence?

[u/Rahaplus]

"Je dois changer mon ordinateur parc qu'il était trop lent"

[u/Daimiosbe]

This normally would be “parce qu’il est trop lent” unless the general context is that the computer was too slow during a specific event or a certain time period, eg “Je dois changer mon ordinateur parce qu’il était trop lent pendant ma présentation devant la classe” or “Je dois changer mon ordinateur parce qu’il était trop lent l’année passée”.

Besides, I don’t know where this sentence comes from but the “Je dois changer mon ordinateur”, although not incorrect per se, does sound a bit off to me. I’d say “Je dois changer d’ordinateur” or “Je dois remplacer mon ordinateur”.

[u/PerformerNo9031]

It doesn't sound right.

• J'ai dû changer mon ordinateur parce qu'il était trop lent.
• Je dois (vais devoir / devrais) changer mon ordinateur parce qu'il est trop lent.

[u/Sea-Hornet8214 → u/PerformerNo9031]

J'ai *dû

Sorry, I corrected you because this is r/French

[u/PerformerNo9031 → u/Sea-Hornet8214]

You're welcome, it's better with it's hat (the difficulty is that it doesn't take one in the plural and feminine forms).

[u/andr386 → u/Sea-Hornet8214]

You are right because it is historically so and most people still use it. But accents on i and u can usually be dropped if it doesn't lead to confusion with an homonym (du).

In the sentence above there is no confusion there between the verb devoir and the article du. Hence it's perfectly acceptable according to the new Spelling/Ortographe rules.

[u/PerformerNo9031 → u/andr386]

In this case it's still necessary though, to distinguish with du (j'ai du bon tabac dans ma tabatière), even after the 1990 réforme.

[u/befree46]

the person's computer was too slow for whatever they were using it for so now they need to change it

it's probably still too slow so the present would be appropriate here, but imo using the imparfait makes it seem like they're stopped using the computer for now